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44 results on '"Université de Nantes ( UN )"'

1. On the Antenna Position to Improve the Radiation Pattern Characterization

Author

Romain Contreres, Nicolas Mezieres, Jean-Marie Lerat, Laurent Le Coq, Benjamin Fuchs, Gwenn Le Fur, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), Centre National d'Études Spatiales [Toulouse] (CNES), European Union through the European Regional Development Fund, French Region of Brittany, Ministry of Higher Education and Research, Rennes Métropole and Conseil Départemental 35, through the CPER Project SOPHIE / STIC & Ondes, Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
sparse recovery, Computer science, antenna radiation patterns, Acoustics, Spherical harmonics, 020206 networking & telecommunications, 02 engineering and technology, Antenna measurements, Radiation pattern, Harmonic analysis, Data set, [SPI]Engineering Sciences [physics], Sampling (signal processing), Position (vector), spherical vector wave expansion, 0202 electrical engineering, electronic engineering, information engineering, optimization methods, Electrical and Electronic Engineering, Antenna (radio)
Abstract

International audience; The 3D characterization of radiating structures is a frequently encountered, and yet challenging, procedure. The theoretical sampling criterion often leads to prohibitive measurement duration, especially for antennas embedded on electrically large structures. However, the position of the antenna under test strongly influences the sampling requirements. By appropriately positioning the antenna with respect to the measurement system, it is possible to promote the low spatial frequency part of its spherical harmonic spectrum. We present a post-processing optimization algorithm enabling a systematic and accurate determination of the antenna best position from a given measurement dataset with no prior knowledge. This sooptimized position is exploited to improve the characterization of the antenna radiation pattern without resorting to any additional measurement sample. The proposed algorithm is validated for both near-field simulations and far-field measurements on various radiating structures, including an antenna embedded on a satellite model.

Published
2021

2. Reflecting Luneburg Lenses

Author

Stefano Maci, Enrica Martini, David Gonzalez-Ovejero, Cristian Della Giovampaola, Jorge Ruiz-Garcia, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Department of Information engineering and mathematics [Siena], Università degli Studi di Siena = University of Siena (UNISI), Ministero dellIstruzione dellUniversit e della Ricerca, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Physics::Optics, Beamforming, flat optics, Luneburg lens, metasurface, surface wave, 02 engineering and technology, Refractive index profile, Waveguide (optics), law.invention, [SPI]Engineering Sciences [physics], 03 medical and health sciences, Optics, Planar, law, Beamforming, Abel transform, surface wave, Electrical and Electronic Engineering, 030304 developmental biology, Physics, 0303 health sciences, Luneburg lens, business.industry, 021001 nanoscience & nanotechnology, Lens (optics), metasurface, Reflection (physics), 0210 nano-technology, business, flat optics, Refractive index
Abstract

International audience; This paper presents the exact closed-form solution for a new planar lens, hereinafter referred to as Reflecting Luneburg Lens (RLL). The proposed structure consists of two stacked parallel plate waveguides of circular shape. The rays generated by a point source located at the periphery of the bottom waveguide propagate along curvilinear paths, whose trajectories result from a variable refractive index profile with azimuthal symmetry. Then, these rays encounter a reflecting boundary and emerge all parallel in the upper uniform waveguide. The behavior of this lens resembles that of a flat Luneburg lens, with the fundamental difference that it works in reflection. The exact refractive index profile is found by solving the non-linear integral equation of ray-congruence trough a truncated Abel transform method. The concept is numerically verified through different implementations of the effective refractive index profile, including a metasurface-based implementation. The proposed lens triggers new possibilities that the normal flat Luneburg lens does not offer, and it is applicable in a large variety of microwave, terahertz and optical devices.

Published
2021

3. Multibeam Si/GaAs Holographic Metasurface Antenna at W-Band

Author

Mauro Ettorre, Goutam Chattopadhyay, David Gonzalez-Ovejero, Ronan Sauleau, Vincent Fusco, Choonsup Lee, Nacer Chahat, Okan Yurduseven, Queen's University [Belfast] (QUB), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), Advanced Component Technology (ACT) Program, Jet Propulsion Laboratory, California Institute of Technology (CALTECH)-NASA, Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Beam steering, 02 engineering and technology, 7. Clean energy, Directivity, antenna, law.invention, Metamaterial, [SPI]Engineering Sciences [physics], Optics, Planar, W band, law, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Reflection coefficient, Physics, Parabolic reflector, business.industry, silicon, 020206 networking & telecommunications, beam shaping, gallium arsenide, metasurface, millimeterwave, holography, Antenna (radio), business, Waveguide
Abstract

International audience; We demonstrate a silicon (Si)-gallium arsenide (GaAs) semiconductor based holographic metasurface antenna operating at 94 GHz. The metasurface antenna molds the radiated beam by resorting to a holographic approach involving the modulation of a guided-mode generated by a pillbox beam former. The pillbox beam former is fed by three integrated horns in Substrate Integrated Waveguide (SIW) technology located in the focal plane of the parabolic reflector of the pillbox beam former. The three horns correspond to three independent beams and allow beam steering by switching from one feed to another. The proposed metasurface antenna is planar and extremely lowprofile, thus suitable for small platforms such as CubeSats/SmallSats. A prototype validates the concept demonstrating a directivity as high as 31.9 dBi and a reflection coefficient lower than-15 dB at 94 GHz.

Published
2021

4. Acceleration of the Computation of the Method of Moments EFIE Impedance Matrix From an Updated Fraunhofer Criterion

Author

Christophe Bourlier, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
[SPI.OTHER]Engineering Sciences [physics]/Other, Radar cross-section, Multiple integral, Mathematical analysis, 020206 networking & telecommunications, Basis function, 02 engineering and technology, Radar cross section, Method of moments (statistics), Electric-field integral equation, Impedance parameters, Integral equation, [SPI.TRON]Engineering Sciences [physics]/Electronics, Electric Field Integral Equation, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, fast algorithm, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Galerkin method, Method of Moments, Mathematics
Abstract

International audience; This paper deals with the acceleration of the computation of the impedance matrix obtained from the electric field integral equation (EFIE) discretized by the Galerkin method of moment (MoM) with Rao-Wilton-Glisson basis functions. The elements of the impedance matrix need to calculate a double integral (quadruple integral) over two planar triangles, which is typically done from two numerical Gauss-Legendre integrations. For far-field interactions, this integration can be done analytically by introducing a criterion for which the resulting closed-form expression is valid. This approximation is tested on a sphere and a concave cavity-shaped object, for which the results show that the time saving factor is about 20, with a mean difference of 0.1-0.5 dB on the radar cross section (RCS) compared to that obtained from two numerical integrations.

Published
2021

5. Reconfigurable Antenna Array With Reduced Power Consumption—–Synthesis Methods and Experimental Validations in S-Band

Author

Laurent Leze, Sébastien Palud, Franck Colombel, Benjamin Fuchs, Stéphane Avrillon, Seydouba Fofana, TéléDiffusion de France (TDF), Groupe TDF, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Union through the European Regional Development Fund, TDF, Liffré, France, French Region of Brittany, Ministry of Higher Education and Research, Rennes Métropole and Conseil Départemental 35, through the CPER Project SOPHIE/STIC and Ondes, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Reconfigurable antenna, Computer science, Amplifier, 020206 networking & telecommunications, 02 engineering and technology, Radiation, Arbitrary waveform generator, Radiation pattern, Power (physics), law.invention, Antenna array, [SPI]Engineering Sciences [physics], Dipole, law, 0202 electrical engineering, electronic engineering, information engineering, Baseband, Electronic engineering, S band, Electrical and Electronic Engineering
Abstract

International audience; The design and realization of a reconfigurable antenna array operating in the 3.4-3.8 GHz band is presented. Array synthesis methods are developed to reduce the power consumption and are experimentally validated by measurements. The array is composed of 16 dual-polarized dipoles whose excitations are provided by a baseband arbitrary waveform generator. The array is able to radiate simultaneously two or more focused beams in one plane over a scanning range of ±45°, these beams can be reconfigured at will. To achieve these radiation pattern requirements while reducing as much as possible the array power consumption, specific antenna array synthesis tools are developed. In particular, the way to synthesize two sparse arrays at two frequencies having common switched-off antennas is proposed and described. This strategy, together with the synthesis of uniform amplitude excitations, enables to harness the consumption characteristics of power amplifiers. This energy-efficient synthesis means that two mobile operators can share the same antenna array. Several representative measurement results of the array prototype validate the radiation performances and experimentally demonstrate the achieved reduction of power consumption.

Published
2021

6. 2 Bit Reconfigurable Unit-Cell and Electronically Steerable Transmitarray at $Ka$ -Band

Author

Ronan Sauleau, Antonio Clemente, Laurent Dussopt, Kien Pham, Fatimata Diaby, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Grenoble Alpes (UGA), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Vietnam National University - Ho Chi Minh City (VNU-HCM), ANR-14-CE28-0023, National Research Agency through the project 'TRANSMIL', ANR-14-CE28-0023,TRANSMIL,Réseaux transmetteurs reconfigurables pour le dépointage et la formation de faisceau en bande millimétrique(2014), Laboratoire d'Electronique et des Technologies de l'Information (CEA-LETI), Université Grenoble Alpes (UGA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Institut d'Electronique et de Télécommunications de Rennes (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Nantes (UN)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
discrete lens, Fabrication, Aperture, electronically steerable antenna, Transmitarray antennas, Phase (waves), beam steering, 02 engineering and technology, [SPI]Engineering Sciences [physics], Bandwidth, Optics, Apertures, 0202 electrical engineering, electronic engineering, information engineering, Bandwidth (computing), Prototypes, Ka band, Computer architecture, Electrical and Electronic Engineering, Pencil-beam scanning, P-i-n diodes, Patch antennas, Diode, Physics, business.industry, Linear polarization, 020206 networking & telecommunications, Ka-band, beam forming, business
Abstract

This communication presents the design, optimization, fabrication, and characterization of an electronically steerable transmitarray (TA) with 2 bits of phase quantization per unit cell. The proposed TA operates in linear polarization at Ka -band and is composed of $14\times14$ reconfigurable unit-cells. Four p-i-n diodes are integrated on each unit-cell to control the radiated field phase distribution across the TA aperture. The prototype demonstrates experimentally pencil beam scanning over a $120^{\circ } \times 120^{\circ }$ window, a maximum gain at broadside of 19.8 dBi, and a 3 dB fractional bandwidth of 16.2%.

Published
2020

7. Experimental Validation of a Correcting Coupling Mechanism to Extend the Scanning Range of Narrowband Phased Array Antennas

Author

Isabelle Le Roy-Naneix, Aurelien Ayissi Manga, Christian Renard, Raphaël Gillard, Renaud Loison, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Thales Airborne Systems, THALES Airborne Systems, Thales Defence Mission Systems, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Coupling, Radar, Phased array, Computer science, Impedance matching, 020206 networking & telecommunications, Context (language use), 02 engineering and technology, Microstrip, law.invention, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Narrowband, antenna arrays, law, Surface wave, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, surface wave, scan blindness, coupling, Electrical and Electronic Engineering
Abstract

International audience;  Abstract-This paper presents a technique designed to extend the scanning range of a probe-fed patch array whose performances are limited by scan blindness, due to a strong surface wave coupling. The current framework relates to the context of radar applications requiring a large scanning range (up to 60°) and where no inter-element spacing modification is possible as a result of strong T/R modules integration constraints. The proposed solution is based on the introduction of an additional correcting coupling within the array, by means of microstrip lines connecting the sources two by two. A thorough step-by-step description of the design methodology is introduced. It is then implemented in the case of a single-polarized 10-element patch array operating in X band. Simulation results as well as an experimental validation of the concept are presented. They assess the effective improvement of the active impedance matching and realized gain resulting from the use of connecting lines.

Published
2020

8. Circularly Polarized Fabry–Perot Antenna Using a Hybrid Leaky-Wave Mode

Author

Herve Legay, Antoine Calleau, Mauro Ettorre, Maria Garcia-Vigueras, Ronan Sauleau, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Thales Alenia Space (TAS), THALES, Brittany Region through the ARED (Allocations de Recherche Doctorale) program, Thales Alenia Space (Toulouse) in the framework of the joint laboratory MERLIN, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Thales Alenia Space [Toulouse] (TAS), THALES [France], and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Physics, leaky-wave antennas, Axial ratio, business.industry, Linear polarization, spectral Green's functions, 020206 networking & telecommunications, Fabry-Perot antennas, 02 engineering and technology, [SPI.TRON]Engineering Sciences [physics]/Electronics, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Optics, circular polarization, Dispersion (optics), 0202 electrical engineering, electronic engineering, information engineering, Tensor, Electrical and Electronic Engineering, Antenna (radio), business, Electrical impedance, Circular polarization, Fabry–Pérot interferometer
Abstract

International audience; A spectral Green's function approach is developed here to analyze Fabry-Perot antennas for the generation of circular polarization. The structure consists of a single cavity, created between a partially reflective surface and a high impedance surface, fed by a low directive linearly polarized source. The elements in the antenna are characterized by tensor impedances. This frame allows to conceive a circularly polarized antenna supporting a single hybrid leaky-wave mode. By means of a residue analysis, it is demonstrated that the use of a single hybrid leaky mode is sufficient to generate circular polarization. The tool is validated by an antenna design matched over a relative bandwidth of 28.5% with an axial ratio lower than 3 dB.

Published
2019

9. Long Slot Array Fed by a Nonuniform Corporate Feed Network in PPW Technology

Author

Mauro Ettorre, Thomas Potelon, Ronan Sauleau, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Union through the European Regional Development Fund (ERDF), Ministry of Higher Education and Research, Brittany and Rennes Metropole through the CPER Project SOPHIE/STIC Ondes, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Physics, high-gain antenna, Acoustics, millimeter-wave antenna, 020206 networking & telecommunications, parallel-plate waveguide (PPW) technology, 02 engineering and technology, 7. Clean energy, [SPI.TRON]Engineering Sciences [physics]/Electronics, Stub (electronics), Antenna efficiency, Maximum efficiency, Antenna array, Feed network, Transverse plane, low-sidelobe level (SLL) antenna, slot array, Broadband antenna, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Broadband antennas, continuous transverse stub (CTS) antenna, Excitation
Abstract

International audience; We present here a novel architecture of high-gain continuous transverse stub (CTS) antenna array operating at E-band (71-86 GHz) with reduced sidelobe level (SLL). The antenna consists of an array of 16 long slots excited by a nonuniform parallel-plate waveguide (PPW) corporate feed network. The nonuniform excitation is achieved by the design of asymmetrical power dividers in PPW technology, for which simple analytical models are provided. Full-wave simulations are validated by measurements of a prototype fabricated in aluminum. The SLL is lower than -28dB in the E-plane. Such an SLL is 15 dB lower than classical parallel-fed CTS arrays. The overall antenna SLL remains below -18 dB over the 75-86 GHz band. Its mean radiation efficiency is 60%, and the maximum efficiency of 85% is reached at 86 GHz.

Published
2019

10. Parametric Optimization of a Non-Foster Circuit Embedded in an Electrically Small Antenna for Wideband and Efficient Performance

Author

Ala Sharaiha, Hussein Jaafar, Dominique Lemur, Sylvain Collardey, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Regional Development Fund, Ministry of Higher Education and Research, Brittany and Rennes Métropole through the Contrat de Plan Etat Region (CPER) Project SOPHIE/STIC and Ondes, Direction Général de l’Armement, Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
non-foster matching, Computer science, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, Bandwidth (signal processing), Astrophysics::Instrumentation and Methods for Astrophysics, 020206 networking & telecommunications, 02 engineering and technology, 7. Clean energy, Capacitance, miniaturization, [SPI]Engineering Sciences [physics], Electrically small antenna, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Miniaturization, ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS, Electrically small atenna, Electrical and Electronic Engineering, Wideband, Electrical impedance, Monopole antenna, Computer Science::Information Theory, Negative impedance converter
Abstract

International audience; In this paper, we present the design of a small, wideband antenna with an embedded non-Foster circuit. The design procedure is based on modeling the antenna in the presence of the EM model of the negative impedance converter (NIC) and trying to optimize the components and location of this active circuit inside the antenna. The EM modeling of the circuit provides the possibility to identify the key parameters that mostly affect the performance of the antenna in terms of bandwidth and efficiency. These parameters are then optimized accordingly. This procedure is applied on a monopole antenna, which has its natural resonance at 2.2 GHz. With an embedded non-Foster circuit, the antenna is miniaturized to cover wideband frequencies around 900 MHz. Two examples are considered for different NIC topologies, after optimizing the components of the NIC, the best performance was given by the second antenna, which exhibits an impedance bandwidth of 50% (0.84-1.45 GHz) and total efficiency of 25%. The measurement results of both antennas are in good agreement with simulations showing a significant enhancement with respect to the passive antenna.

Published
2019

11. Method of Moments Simulation of Modulated Metasurface Antennas With a Set of Orthogonal Entire-Domain Basis Functions

Author

David Gonzalez-Ovejero, Modeste Bodehou, Isabelle Huynen, Christophe Craeye, Université Catholique de Louvain = Catholic University of Louvain (UCL), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), FRIA (Fonds pour la formation a la Recherche dans l'Industrie et dans l'Agriculture) grant from the Belgium FNRS (Fonds National de la Recherche Scientifique) fund, Marie Curie International Outgoing Fellowship through the 7th European Community Framework Program, UCL - SST/ICTM/ELEN - Pôle en ingénierie électrique, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Hankel transform, leaky-wave antennas, Zernike polynomials, Gaussian, Mathematical analysis, 020206 networking & telecommunications, Basis function, 02 engineering and technology, Electric-field integral equation, Method of moments (statistics), method of moments (MoM), Integral equation, metasurfaces (MTSs), [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, symbols.namesake, Matrix (mathematics), spectral domain methods, 0202 electrical engineering, electronic engineering, information engineering, symbols, Electrical and Electronic Engineering, Basis functions, impedance boundary condition (IBC)
Abstract

International audience; A family of orthogonal and entire-domain basis functions (named Fourier-Bessel) is proposed for the analysis of circular modulated metasurface (MTS) antennas. In the structures at hand, the MTS is accounted for in the electric field integral equation (EFIE) as a sheet transition impedance boundary condition on the top of a grounded dielectric slab. The closed-form Hankel transform of the Fourier-Bessel basis functions (FBBFs) allows one to use a spectral domain formulation in the method-of-moments (MoM) solution of the EFIE. Moreover, these basis functions are fully orthogonal, which implies that they are able to represent the global evolution of the current distribution in a compact form. FBBFs also present a better filtering capability of their spectrum compared to other well-known orthogonal families such as the Zernike functions. The obtained MoM matrix is sparse and compact, and it is thus very well-conditioned and can be efficiently computed and inverted. The numerical results based on the proposed decomposition are presented and compared with those based on the use of the Gaussian ring basis functions and with the full-wave analysis of MTS antennas implemented with small printed elements. A very good agreement is observed.

Published
2019

12. Characteristic Modes Approach to Design Compact Superdirective Array With Enhanced Bandwidth

Author

Sylvain Collardey, Hussein Jaafar, Ala Sharaiha, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Ministry of Higher Education and Research, Brittany and Rennes Métropole through the CPER Project SOPHIE/STIC & Ondes, Direction Général de l’Armement, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
010302 applied physics, Physics, Compact antennas, Acoustics, Bandwidth (signal processing), 020206 networking & telecommunications, 02 engineering and technology, 01 natural sciences, Directivity, Narrow bandwidth, network characteristic modes (NCMs), [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Modal, Multiple frequency, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Wideband, multiport antennas, Electrical impedance, Excitation, superdirectivity
Abstract

International audience; Superdirective arrays have become the key technique in enhancing the directivity of electrically small antennas. By forming an array of closely spaced unit elements, a high directivity can be achieved. Despite the high directivity, these arrays suffer from narrow bandwidth and low efficiency. In this paper, we present an approach to enhance the bandwidth of superdirective arrays using the network characteristic modes. The key step is to use an internally loaded compact wideband unit element. The loads inside the unit element are used to manipulate the characteristic modes in order to optimize its impedance bandwidth. A two-element endfire array is then formed. The modal coefficients of the characteristic fields are then optimized at multiple frequency points in order to radiate a maximal directivity in the endfire direction. The best current excitation that can maintain a constant directivity as a function of frequency is then deduced. Finally, a feeding network that can provide the desired excitation at the array ports is designed and integrated on the array system, where the 1 dB directivity bandwidth is about 23% with Dmax=7.1 dBi. The antenna impedance bandwidth is equal to 15%.

Published
2018

13. 2-D Van Atta Array of Wideband, Wideangle Slots for Radiative Wireless Power Transfer Systems

Author

Mauro Ettorre, Waleed Alomar, Anthony Grbic, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), King Abdulaziz City for Science and Technology, Conseil National de la Recherche Scientifique, University of Rennes 1, Rennes, France, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Physics, Aperture, time reversal, Amplifier, Acoustics, 020208 electrical & electronic engineering, Bandwidth (signal processing), wireless power transfer, 020206 networking & telecommunications, Van Atta antennas, 02 engineering and technology, law.invention, Antenna array, [SPI]Engineering Sciences [physics], law, Retrodirective antennas, 0202 electrical engineering, electronic engineering, information engineering, wideband arrays, Wireless power transfer, Dipole antenna, Electrical and Electronic Engineering, Wideband, Coaxial
Abstract

International audience; We present a 2-D Van Atta array for far-field wireless power transfer systems. The antenna array is made up of wideband, wideangle long slots. The monostatic radar cross section (RCS) of the finite array is derived by windowing the aperture field distribution of the corresponding infinite case. It is shown that for oversampled apertures, the array behaves as an ideal Van Atta reflector. Therefore, the proposed solution can collect and reradiate the total power impinging on it from a remote source over a large field of view and bandwidth. The array design is presented and validated through measurements over a relative bandwidth of 24% centered at a frequency of 5.8 GHz. The array consists of four slots, each fed by eight coaxial ports. Coaxial cables are used to connect pairs of feeds in a Van Atta configuration. A bidirectional amplifier is also introduced into the Van Atta scheme to amplify the collected energy before retransmission to a possible moving user for wireless power transfer. Off-The-shelf components are used to implement the bidirection amplifier. The amplifier is matched across the bandwidth of the array and provides 5 dB gain. Monostatic RCS measurements show that the array exhibits-10 dB beamwidths of about 118° and 80° in the E-and H-planes, over the entire bandwidth. In addition, it is shown that when the array ports are terminated with matched loads, the antenna RCS is reduced by approximately-15 dB with respect to the Van Atta case. This experimentally confirms that the array collects the total energy impinging from a remote source. © 1963-2012 IEEE.

Published
2018

14. Broadband and Broad-Angle Multilayer Polarizer Based on Hybrid Optimization Algorithm for Low-Cost Ka-Band Applications

Author

Ronan Sauleau, Darwin Blanco, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
planar circuit board, Materials science, Circular polarization (CP), 02 engineering and technology, law.invention, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Optics, law, Transmission line, polarizer, 0202 electrical engineering, electronic engineering, information engineering, Insertion loss, Ka band, Electrical and Electronic Engineering, Circular polarization, Axial ratio, business.industry, Floquet-mode analysis, 020208 electrical & electronic engineering, 020206 networking & telecommunications, Polarizer, [SPI.TRON]Engineering Sciences [physics]/Electronics, Frequency domain, Antenna (radio), business, linear polarization
Abstract

International audience; We present a method to design planar broadband and broad-angle multilayer polarizers. The proposed procedure is based on a hybrid method that combines the analytical transmission line model and the full-wave Floquet analysis in the frequency domain. The unit-cell analysis allows to create a database that relates the geometry with the metasurface impedances. Thus, any kind of geometries (especially those that do not have an equivalent model) can be used. As the database is created for a single-layer structure, the computation time needed for the design process is reduced (compared with the full-stacked unit-cell). As an example, a polarizer is designed as an add-on device that could be integrated to any linearly polarized antenna (without affecting its behavior) to create circular polarization. Experimental results for a five-metasurface-layer design are given, demonstrating insertion loss lower than 0.5 dB and an axial ratio less than 3 dB over the entire band ranging from 24.84 to 30.24 GHz, which corresponds to a fractional bandwidth of 19.6% for an incidence of 0°-50°. © 2018 IEEE.

Published
2018

15. Impact of Antenna Topology and Feeding Technique on Coupling With Human Body: Application to 60-GHz Antenna Arrays

Author

Carole Leduc, Maxim Zhadobov, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), French Ministry of Higher Education and Research, National Center for Scientific Research (CNRS), France, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Acoustics, Random wire antenna, heating, 02 engineering and technology, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], 0202 electrical engineering, electronic engineering, information engineering, body-area networks, Electrical and Electronic Engineering, Omnidirectional antenna, Monopole antenna, Ground plane, dosimetry, Directional antenna, business.industry, Antenna measurement, Astrophysics::Instrumentation and Methods for Astrophysics, 020206 networking & telecommunications, 021001 nanoscience & nanotechnology, 60 GHz, antenna/human body interactions, [SPI.TRON]Engineering Sciences [physics]/Electronics, Antenna efficiency, millimeter-wave (mmW) band, antenna arrays, Optoelectronics, specific absorption rate (SAR), Antenna (radio), 0210 nano-technology, business, 5G, feeding
Abstract

International audience; The 60-GHz band has been identified as an attractive solution for the next-generation mobile networks (5G) as well as for body-centric applications. This paper provides a quantitative comparative analysis of electromagnetic exposure and heating induced by 60-GHz body-mounted antennas. Near-field interaction between representative antenna arrays for off-body communications with three feeding topologies and human body is compared in terms of matching and radiation, as well as in terms of user exposure. The presence of a ground plane results in exposure reduction by more than 70 and 8 times in terms of peak and averaged levels, respectively. Designs allowing to avoid grating lobes allow further reduction of exposure. For considered antenna arrays operating at the maximum allowable power, International Commission on Non-Ionizing Radiation Protection occupational exposure limits are not exceeded. However, only the antennas with a ground plane comply with general public limits. Resulting heating is quantified for on-body millimeter-wave antennas. Detailed analysis is performed for acute and disperse exposures. Numerical results are validated by measurements. Effect of averaging is also investigated. For antennas with a ground plane, heating (typically of several tenths of degrees C) remains within environmental temperature fluctuations. However, the antennas without a ground plane can induce heating locally exceeding 10 degrees C.

Published
2017

16. Fresnel Lens at Millimeter-Wave: Enhancement of Efficiency and Radiation Frequency Bandwidth

Author

Antoine Jouade, Mohamed Himdi, Olivier Lafond, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), UMR CNRS 6164, Université de Rennes 1, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Frequency band, Fresnel zone antenna, Physics::Optics, 02 engineering and technology, Radiation pattern, law.invention, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Optics, law, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Physics, wide band, business.industry, Fresnel lens antennas, 020208 electrical & electronic engineering, Bandwidth (signal processing), Astrophysics::Instrumentation and Methods for Astrophysics, 020206 networking & telecommunications, Fresnel lens, millimeter wave, [SPI.TRON]Engineering Sciences [physics]/Electronics, Lens (optics), high efficiency, Angular aperture, Extremely high frequency, Directive antennas, business
Abstract

International audience; In this paper, the performance of Fresnel lens antennas is investigated in detail. The performance is evaluated in terms of aperture efficiency and stable radiation pattern over a wide frequency band. This paper proposes an efficient technique for enhancing aperture efficiency by smoothly compensating for the spherical phase front arriving upon the lens surface. The feeder has been optimized to fit an axially symmetric cosn-like radiation pattern. For this, an accurate technological process has been used to manufacture a lens that allows for smooth compensation of the phase shift. The lens is compared with a classic Fresnel lens having the same physical dimensions and feeding system. The improvement is validated by measurement, which has revealed a maximum measured gain of 38.9 dBi corresponding to a maximum measured aperture efficiency of 59% with a-2 dB radiation frequency bandwidth of 29.25 GHz around 90 GHz. This amounts to an aperture efficiency enhancement of 60% and-2 dB radiation frequency bandwidth enhancement of 72% as compared with those of the classic Fresnel lens. © 1963-2012 IEEE.

Published
2017

17. Radiative Wireless Power-Transfer System Using Wideband, Wide-Angle Slot Arrays

Author

Anthony Grbic, Mauro Ettorre, Waleed Alomar, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Stanford Synchrotron Radiation Lightsource (SSRL SLAC), SLAC National Accelerator Laboratory (SLAC), Stanford University-Stanford University, UM-KACST Joint Center for Microwave Sensor Technology, Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Directional antenna, business.industry, Time reversal, 020208 electrical & electronic engineering, Bandwidth (signal processing), 020206 networking & telecommunications, Near and far field, Field of view, Van Atta antennas, 02 engineering and technology, Physical optics, Wideband arrays, [SPI.TRON]Engineering Sciences [physics]/Electronics, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Optics, Retrodirective antennas, 0202 electrical engineering, electronic engineering, information engineering, Radiative transfer, Wireless power transfer, Electrical and Electronic Engineering, Wideband, business
Abstract

International audience; This paper analyzes the benefits of using wideband, wide-angle arrays in radiative wireless power-transfer systems. A physical optics (PO) code is used to investigate the focusing capabilities and operating range of two 2-D antennas: Van Atta arrays and phase-conjugate/time-reversal arrays. In the PO analysis, the antennas are assumed to be ideal mirrors, which do not backscatter the impinging energy but rather completely absorb and reemit it. Sources located in both the near and far field of the antennas are considered. It is shown that for distances larger than the mirror size, the two antennas have similar focusing capabilities. In such scenarios, a Van Atta approach is preferred over a phase-conjugate approach due to its ease of implementation. Antenna elements used to realize these arrays/mirrors are typically resonant and exhibit strong backscatter, a limited field of view, and small bandwidth. To overcome these limitations, we propose an array/mirror consisting of long slots fed by parallel plate waveguides. A spectral Green's function approach is used to derive the scattering performance of the infinite array in reception. It is shown that the array can collect the total power impinging from a remote source over a large field of view and bandwidth. The conclusions arrived at for the infinite case are extended to the finite case through full-wave simulations. It is shown that the array can refocus the energy impinging from a close source over a large bandwidth. An infinite magnetic line source is considered as an example. An accurate expression is provided for the voltage distribution across the feed lines of the array. The proposed solution paves the way toward the practical implementation of ideal Van Atta and time-reversal/ phase-conjugate mirrors. The wideband behavior of the array may enable high-power, pulsed retrodirective arrays. © 2017 IEEE.

Published
2017

18. Propagation and Scattering in Ducting Maritime Environments From an Accelerated Boundary Integral Equation

Author

Christophe Bourlier, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes 1 (UR1), Charlier, Sandrine, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Parabolic wave equation, Discretization, Iterative methods, Iterative method, 02 engineering and technology, Refractive index profile, 01 natural sciences, 010309 optics, Optics, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Surface roughness, 14. Life underwater, Electrical and Electronic Engineering, Method of Moments, Mathematics, business.industry, Scattering, [SPI.ELEC] Engineering Sciences [physics]/Electromagnetism, Mathematical analysis, Linear system, Approximation algorithm, 020206 networking & telecommunications, Radar sea surface electromagnetic scattering, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Adaptive Cross Approximation, Atmospheric duct, business
Abstract

International audience; For a two-dimensional problem and at microwaveradar frequencies, in a previous paper, the field scattered bya highly-conducting large rough sea surface in the presenceof a duct having a linear-square refractive index profile hasbeen computed. The FB (Forward-Backward) method has beenapplied to solve the linear system obtained by discretizing theBIE (Boundary Integral Equation) from the MoM (Method ofMoments). To reduce again the complexity in order to solvehuge problems, the SDIM (Subdomain Decomposition IterativeMethod) is applied and combined with the Forward-BackwardSpectral-Acceleration (FB-SA) for the calculation of the surfacecurrents on each sub-surface of the sea. The ACA algorithm isalso applied to accelerate the coupling steps between the subsurface.Finally, this method is tested on the medium having arefractive index of parabolic profile, which is more realistic thana linear profile

Published
2016

19. Leaky-Wave Thinned Phased Array in PCB Technology for Telecommunication Applications

Author

Antonio Montesano Benito, Eva Rajo-Iglesias, Darwin Blanco, Nuria Llombart, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), TEC2013-44019-R, Spanish Government, S2013/ICE-3000, Madrid Regional Government, Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Printed circuit boards, Leaky wave antennas, Phased array, Near and far field, 02 engineering and technology, Grating, leaky-wave antennas (LWAs), Directivity, Scanning antennas, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Printed circuit board, Mode suppression, Reflective surfaces, Optics, Printed circuit boards (PCB), TM0 mode suppression, 0202 electrical engineering, electronic engineering, information engineering, Antenna arrays, Electrical and Electronic Engineering, Reflection coefficient, Telecommunication applications, Thinned array, Physics, Phased-array optics, business.industry, 020208 electrical & electronic engineering, 020206 networking & telecommunications, [SPI.TRON]Engineering Sciences [physics]/Electronics, Phased array antennas, Traveling wave antennas, phased array, Antennas, Antenna phased arrays, Array gain, Gain enhancement, business, Filtration
Abstract

International audience; We present a practical implementation of a leaky-wave thinned phased array in printed circuit board (PCB) technology. In this paper, we demonstrate that a reduction of the grating lobes, and therefore an improved gain in a thinned phased array, with respect to standard solutions, is achieved by virtue of the angular filtering introduced by a leaky-wave cavity in the far field. The presented array is designed in PCB and integrated with an inductive partial reflective surface. A full study of the performances of the 7 × 7 phased array antenna for several scanning angles and frequencies is presented. This paper shows an improved gain, directivity, grating lobe level, back lobe level, beam efficiency, and active reflection coefficient with respect to a reference solution based on 2 × 2 subarrays. The results are validated via the measurements of a 3 × 3 array prototype. © 2016 IEEE.

Published
2016

20. Multibeam SIW Slotted Waveguide Antenna System Fed by a Compact Dual-Layer Rotman Lens

Author

Laurent Le Coq, Karim Tekkouk, Ronan Sauleau, Mauro Ettorre, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Agence Nationale de la Recherche [ANR-2010-VERS-001301, ANR-12-EMMA-0041-01, ANR-11-ASTR-017-02], DGCIS (DENOTEIC) [FUI 10], GENCI-IDRIS [2014-050779], ANR-10-VERS-0013,AMORCE,Antenne mobile émission réception compacte pour liaison satellite(2010), ANR-12-EMMA-0041,MM-Scan,Système antennaire ultra-compact multi-faisceau et reconfigurable à large champ de vision pour les futures générations de radars automobiles de sécurité active(2012), ANR-11-ASTR-0017,GRAIK,Grand Reflectarray Imageur en bande Ka(2011), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
design, array, substrate, 02 engineering and technology, 7. Clean energy, law.invention, Optics, sensor, law, Broadband, 0202 electrical engineering, electronic engineering, information engineering, Standing wave ratio, Electrical and Electronic Engineering, Reflection coefficient, Physics, Coupling, business.industry, feed, posts, 020208 electrical & electronic engineering, Bandwidth (signal processing), 020206 networking & telecommunications, [SPI.TRON]Engineering Sciences [physics]/Electronics, Lens (optics), ghz, business, Waveguide, radar, Slotted waveguide
Abstract

A multibeam antenna system fed by a compact Rotman lens is presented in multilayer substrate integrated waveguide (SIW) technology. The lens is implemented in two layers using a new transition based on several star-shaped coupling slots and an SIW integrated reflector. Compared to standard rectangular coupling slots, this transition is broadband and maximizes power transfer between the two layers of the lens regardless the position of the beam port along the focal arc of the Rotman lens. The radiating part is an array of 15 slotted waveguides. These waveguides are centrally fed to enhance their bandwidth and reduce the “long line effect.” To validate the proposed concepts, an antenna system has been prototyped at 24.15 GHz. The designed transition leads to a physical size reduction of about 50% for the Rotman lens, and more than 33% for the antenna footprint compared to standard single-layer implementations. The experimental results demonstrate a scanning range of $\pm {33}^\circ $ and a 4% bandwidth for $\text{VSWR} ; the isolation between input ports is better than $- {10}\;\text{dB}$ .

Published
2016

21. Beam-Forming Capabilities of Waveguide Feeds Assisted by Corrugated Flanges

Author

Artem Boriskin, A. A. Kirilenko, Maxim Zhadobov, Ronan Sauleau, S. O. Steshenko, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Agence Nationale de Securite Sanitaire (ANSES), France under National Research Program for Environmental and Occupational Health (project OMCell), European Science Foundation (ESF) under RNP NEWFOCUS program, Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
horn antenna, lens, aperture efficiency, leaky modes, design, 02 engineering and technology, Stopband, Radiation, Waveguide (optics), Radiation pattern, periodic printed structures, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Optics, reflectors, 0202 electrical engineering, electronic engineering, information engineering, surface, Electrical and Electronic Engineering, Physics, business.industry, 020208 electrical & electronic engineering, 020206 networking & telecommunications, Polarization (waves), [SPI.TRON]Engineering Sciences [physics]/Electronics, Horn antenna, Surface wave, business, radiation-pattern, band, Beam (structure)
Abstract

International audience; The physical mechanisms behind the formation of shaped-beam radiation patterns by flat horns (i. e., open ended waveguide feeds with finite-size corrugated flanges) are studied in a rigorous manner using the singular integral equation (SIE) approach. The problem is considered for TM polarization in the two-dimensional (2-D) formulation. First, dispersion curves of periodic grating are presented and used to analyze the modes supported by the waveguide flanges. This includes the surface wave, stopband, and leaky-wave regimes. The modes corresponding to the poles on the bottom "nonphysical" Riemann sheets are also considered. Finally, various types of radiation patterns produced by flat horns with gratings operating in different regimes are illustrated with an emphasis on generating sectoral beams being of interest for many practical applications. The results are validated via comparison with full-wave three-dimensional (3-D) analysis.

Published
2015

22. Circularly Polarized Transmitarray With Sequential Rotation in Ka-Band

Author

Luca Di Palma, Laurent Dussopt, Ronan Sauleau, Philippe Pouliguen, Patrick Potier, Antonio Clemente, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), DGA Mission Recherche et Innovation Scientifique (DGA MRIS), DGA, French Ministry of Defense, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
loss 0.2 dB, discrete lens, Circular polarization (CP), CP unit cell, electromagnetic wave polarisation, Ka band, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Bandwidth, millimetre wave antenna arrays, Optics, Transmitting antennas, Phase resolution, Array performance, sequential rotation, Insertion loss, Gain, Electrical and Electronic Engineering, Gain measurement, Arrays, right-handed CP, word length 1 bit, Circular polarization, Physics, linearly polarized source, frequency 30 GHz, microwave antenna arrays, Linear polarization, business.industry, Axial ratio, antenna radiation patterns, Bandwidth (signal processing), full array configuration, [SPI.TRON]Engineering Sciences [physics]/Electronics, hybrid in-house simulation tool, circular polarization, transmitarray, axial ratio bandwidth, business, circularly polarized transmitarray antenna
Abstract

International audience; We present here the design and demonstration of a circularly polarized (CP) transmitarray antenna operating in Ka-band and illuminated by a linearly polarized (LP) source. The proposed design is based on a CP unit-cell with simulated insertion loss of 0.2 dB at 30 GHz. In order to improve the axial ratio (AR) bandwidth, the sequential rotation technique is applied to the full array configuration. A model based on a hybrid in-house simulation tool is also proposed to predict accurately the array performance. The realized prototype, formed by 400 unit-cells, has 1 bit of phase resolution. The measured broadside gain is 22.8 dBi at 30 GHz with a 3-dB bandwidth of 20% in right-handed CP (RHCP). The obtained 3-dB AR bandwidth of 24.4% is comparable with higher resolution designs

Published
2015

23. Gaussian Ring Basis Functions for the Analysis of Modulated Metasurface Antennas

Author

David Gonzalez-Ovejero, Stefano Maci, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Siena = University of Siena (UNISI), AO/1-7069/12/NL/MH, European Space Agency, W911NF-13-1-0454, U.S. Army Research Laboratory through USAIT-CA, 7th European Community Framework Programme, Jet Propulsion Laboratory, California Institute of Technology, National Aeronautics and Space Administration, Marie Curie International Outgoing Fellowship, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
spectral-domain approach, method of moments, Basis (linear algebra), leaky-wave antennas, Gaussian, Mathematical analysis, Basis function, basis functions, Method of moments (statistics), Condensed Matter Physics, Impedance parameters, System of linear equations, metasurfaces, Integral equation, Electrical and Electronic Engineering, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, symbols.namesake, symbols, Electrical impedance, ComputingMilieux_MISCELLANEOUS, Mathematics
Abstract

This paper presents a novel type of basis functions, whose spectral- and space-domain properties can be exploited for the efficient method of moments (MoM) analysis of planar metasurface (MTS) antennas. The effect of the homogenized MTS is introduced in the integral equation as an impedance boundary condition (IBC). The proposed basis functions are shaped as Gaussian-type rings with small width and linear azimuthal phase. The analytical form of the spectrum of the Gaussian ring basis allows for a closed-form evaluation of the MoM impedance matrix’s entries. Moreover, these basis functions account for the global evolution of the surface current density in an effective manner, reducing the size of the MoM system of equations with respect to the case of subdomain basis functions. These features allow one to carry out a direct solution for problems with a diameter of up to 15 wavelengths in less than 1 min using a conventional laptop. The applicability on practical antennas has been tested through the full-wave analysis of MTS antennas implemented with small printed elements.

Published
2015

24. Active Impedance of Infinite Parallel-Fed Continuous Transverse Stub Arrays

Author

Mauro Ettorre, Massimiliano Casaletti, Ronan Sauleau, Francesco Foglia Manzillo, Nicolas Capet, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Electronique et Electromagnétisme (L2E), Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National d'Études Spatiales [Toulouse] (CNES), 619563, European Union Seventh Framework Programme, CNES, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Physics, Magnetic domain, business.industry, Acoustics, 020208 electrical & electronic engineering, 020206 networking & telecommunications, 02 engineering and technology, Green’s function, Broadband communication, broadband antennas, Stub (electronics), [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Transverse plane, long slots, parallel plate waveguides, Optics, Broadband, 0202 electrical engineering, electronic engineering, information engineering, Antenna arrays, Electrical and Electronic Engineering, Broadband antennas, business, Electrical impedance, Scan angle
Abstract

International audience; This work introduces a rigorous and effective modeling framework for the continuous transverse stub (CTS) array, based on a spectral Green’s function approach. A multi-modal expansion of the equivalent currents over the slots is used to derive an accurate expression for the active impedance of an infinite array. This formula is validated through comparisons with full-wave simulations when the array scans in principal planes. The mathematical formulation highlights the broadband properties of CTS arrays and accurately predicts the impact of the geometrical parameters on the active impedance, as a function of frequency and scan angle. The discussion of the results provides physical insights to outline effective design strategies.

Published
2015

25. Dual Circularly Polarized Reflectarray With Independent Control of Polarizations

Author

Simon Mener, Patrick Potier, Raphaël Gillard, Ronan Sauleau, Anthony Bellion, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), DGA Maîtrise de l'information (DGA.MI), Direction générale de l'Armement (DGA), Centre National d’Etudes Spatiales (CNES), Direction Générale de l’Armement (DGA), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Physics, Dual-polarized passive reflectarray, business.industry, Frequency band, Axial ratio, Antenna radiation patterns, Bandwidth (signal processing), 020206 networking & telecommunications, 020302 automobile design & engineering, 02 engineering and technology, [SPI.TRON]Engineering Sciences [physics]/Electronics, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Optics, 0203 mechanical engineering, 0202 electrical engineering, electronic engineering, information engineering, Dualcircular polarizations, Electrical and Electronic Engineering, Center frequency, business, ComputingMilieux_MISCELLANEOUS
Abstract

A reflectarray with independent dual-circular polarizations is proposed for the first time. The reflector panel operates in X-band and contains 97 unit-cells. It is made with a lego-type configuration allowing change manually the phase aperture distribution and demonstrating experimentally the independence of both polarizations in the same frequency band. To this end, various beam pointing directions are selected in right-hand and left-hand polarizations. The achieved bandwidth is 790 MHz (9.4% at the center frequency 8.37 GHz) for an axial ratio lower than 3.5 dB with 1.5 dB gain variations.

Published
2015

26. A New Hybrid Method for the Analysis of Surrounded Antennas Mounted on Large Platforms

Author

Patrick Potier, Renaud Loison, Laurent Patier, Raphaël Gillard, Philippe Pouliguen, Benoît Le Lepvrier, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Institut d'Electronique et de Télécommunications de Rennes (IETR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Centre National de la Recherche Scientifique (CNRS), DGA Mission Recherche et Innovation Scientifique (DGA MRIS), DGA, DGA Maîtrise de l'information (DGA.MI), Direction générale de l'Armement (DGA), Centre National d'Études Spatiales [Toulouse] (CNES), CNES / DGA, Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
antenna on structure, Computer science, Physics::Optics, Data_CODINGANDINFORMATIONTHEORY, 02 engineering and technology, law.invention, multi-scale method, Optics, Hardware_GENERAL, law, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS, Time domain, Electrical and Electronic Engineering, Wideband, Computer Science::Information Theory, Reconfigurable antenna, Directional antenna, business.industry, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, 020208 electrical & electronic engineering, Finite-difference time-domain method, 020206 networking & telecommunications, Terms--hybrid methods, Physical optics, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, DG-FDTD, IPO, Antenna (radio), business
Abstract

International audience; An efficient technique to provide fast and accurate analysis of wide-band surrounded antennas mounted on electrically large platforms is presented and validated in this paper. The hybrid method combines Dual-Grid FDTD (DG-FDTD) with Iterative Physical Optics (IPO) to analyze on-platform antenna radiation. In section IV of this paper, DG-FDTD/IPO is applied to the analysis of a wide-band antenna mounted on a vehicle. The ability to address the problem of antenna placement is also demonstrated.

Published
2014

27. On-Body Propagation at 60 GHz

Author

Ronan Sauleau, Maxim Zhadobov, Nacer Chahat, Guido Valerio, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Physics, Horizontal and vertical, business.industry, 020302 automobile design & engineering, 020206 networking & telecommunications, 02 engineering and technology, Polarization (waves), Imaging phantom, Computational physics, Dipole, Optics, 0203 mechanical engineering, Path gain, 0202 electrical engineering, electronic engineering, information engineering, Exponent, Electrical and Electronic Engineering, business, ComputingMilieux_MISCELLANEOUS
Abstract

The on-body propagation at 60 GHz is studied analytically, numerically and experimentally using a skin-equivalent phantom. First, to provide analytical-based fundamental models of path gain, the theory of propagating waves near a flat phantom is studied by considering vertical and horizontal elementary dipoles. The analytical models are in excellent agreement with full-wave simulations. For a vertically polarized wave, a minimum power decay exponent of 3.5 is found. Then, propagation on the body is investigated experimentally in vertical and horizontal polarizations using two linearly-polarized open-ended waveguides. The analytical models fit very well with the measurements. Furthermore, the effect of polarization on the antenna performance is studied numerically and experimentally.

Published
2013

28. On the Relationship Between Multiple-Scattering Macro Basis Functions and Krylov Subspace Iterative Methods

Author

David Gonzalez-Ovejero, Christophe Craeye, N. A. Ozdemir, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université Catholique de Louvain = Catholic University of Louvain (UCL), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Mathematical optimization, Iterative method, 020206 networking & telecommunications, Basis function, 02 engineering and technology, Krylov subspace, System of linear equations, Impedance parameters, 01 natural sciences, Linear subspace, 010309 optics, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Orthogonality, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Algorithm, Orthogonalization, ComputingMilieux_MISCELLANEOUS, Mathematics
Abstract

A mathematical link is provided between the Krylov subspace iterative approach based on the full orthogonalization method (FOM) and the macro basis functions (MBF) approach based on a multiple-scattering methodology. The link refers to the subspaces created by those methods as well as to the orthogonality conditions which they satisfy. Both approaches are applied to the same method-of-moments (MoM) system of equations that is preconditioned based on a closest-interaction rule, and where blocks of the MoM impedance matrix are compressed using a rank-revealing method. MBF and FOM approaches are compared numerically, with a special attention given to accuracy, for perfectly conducting objects, comprising an array of tapered-slot antennas, spheres and an aircraft. The respective advantages of both methods are briefly discussed and further prospects are given.

Published
2013

29. Guest Editorial for the Special Issue on Antennas and Propagation at mm- and Sub mm-Waves

Author

Jorge R. Costa, Jiro Hirokawa, Ronan Sauleau, Carlos A. Fernandes, Duixian Liu, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Focus (computing), business.industry, Computer science, Terahertz radiation, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020206 networking & telecommunications, 02 engineering and technology, Optics, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Millimeter, Electrical and Electronic Engineering, business, ComputingMilieux_MISCELLANEOUS
Abstract

The 43 papers in this special issue provide an overview of recent advances and emerging applications in millimeter and sub-millimeter waves, especially beyond 60 GHz up to terahertz, with strong focus towards practical implementable solutions.

Published
2013

30. Bridging the Gap Between the Babinet Principle and the Physical Optics Approximation: Scalar Problem

Author

Y. A. Yahia, Christophe Bourlier, Nicolas Pinel, Philippe Pouliguen, Gildas Kubicke, DGA Maîtrise de l'information (DGA.MI), Direction générale de l'Armement (DGA), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), DGA Mission Recherche et Innovation Scientifique (DGA MRIS), DGA, Charlier, Sandrine, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Physics, Surface (mathematics), 010504 meteorology & atmospheric sciences, Field (physics), Wave propagation, Scattering, Forward scatter, Mathematical analysis, 020206 networking & telecommunications, Near and far field, 02 engineering and technology, Physical optics, 01 natural sciences, Classical mechanics, 0202 electrical engineering, electronic engineering, information engineering, Specular reflection, Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

For a two-dimensional (2-D) problem, this paper shows that the Babinet Principle (BP) can be derived from the physical optics (PO) approximation. Indeed, following the same idea as Ufimtsev, from the PO approximation and in far-field zone, the field scattered by an object can be split up into a field that mainly contributes around the specular direction (illuminated zone) and a field that mainly contributes around the forward direction (shadowed zone), which is strongly related to the scattered field obtained from the BP. The only difference relies on the integration surface. We also show mathematically that the involved integral does not depend on the shape of the object, which then corresponds to the BP. Simulations are provided to illustrate the link between the BP and PO.

Published
2011

31. A New Multimode Antenna for MIMO Systems Using a Mode Frequency Convergence Concept

Author

Yann Mahe, S. Toutain, Stéphane Avrillon, Julien Sarrazin, Avrillon, Stéphane, BK Birla Institute of Technology (BKBIET), BK Birla Institute of Technology, Institut de Recherche en Electrotechnique et Electronique de Nantes Atlantique EA4642 (IREENA), Institut Universitaire de Technologie Saint-Nazaire (IUT Saint-Nazaire), Université de Nantes (UN)-Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Institut Universitaire de Technologie - La Roche-sur-Yon (IUT La Roche-sur-Yon), Université de Nantes (UN)-Université de Nantes (UN), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche en Energie Electrique de Nantes Atlantique EA4642 (IREENA), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Patch antenna, Reconfigurable antenna, business.industry, Antenna measurement, Random wire antenna, Electrical engineering, 020302 automobile design & engineering, 020206 networking & telecommunications, 02 engineering and technology, [SPI.TRON] Engineering Sciences [physics]/Electronics, [SPI.TRON]Engineering Sciences [physics]/Electronics, law.invention, Antenna efficiency, Folded inverted conformal antenna, Microstrip antenna, 0203 mechanical engineering, law, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Electrical and Electronic Engineering, Antenna (radio), business, ComputingMilieux_MISCELLANEOUS, Computer Science::Information Theory
Abstract

A new multimode antenna is proposed in this paper. The structure is based on a mode frequency convergence concept. A microstrip square patch antenna is modified in order to force different modes to resonate at the same frequency. Then, with a common/differential excitation, these modes can be fed independently. Thus, three radiation patterns are available simultaneously, thereby producing diversity. With dimensions less than a guided wavelength (≈ 0.88λg), the proposed structure is well suited to reduce the size of multiple antennas used in diversity applications such as MIMO systems. The antenna has been designed in the 2.45 GHz band for Wi-Fi applications.

Published
2011

32. Interpolatory Macro Basis Functions Analysis of Non-Periodic Arrays

Author

David Gonzalez-Ovejero, Christophe Craeye, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université Catholique de Louvain = Catholic University of Louvain (UCL), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Computation, Mathematical analysis, 020206 networking & telecommunications, Basis function, 02 engineering and technology, Function (mathematics), Method of moments (statistics), 01 natural sciences, Expression (mathematics), Antenna array, [SPI]Engineering Sciences [physics], [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Antenna (radio), Representation (mathematics), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Mathematics
Abstract

An efficient method-of-moments (MoM) technique for analyzing non-periodic antenna arrays of identical elements with fixed orientation is presented. The proposed method, which uses macro basis functions (MBFs), is based on a compact representation of the interactions between MBFs. These interactions are expressed via a low-order harmonic-polynomial function after an explicit pre-computation of the reaction integrals in a very limited set of relative positions. This is possible for arrays of arbitrary size thanks to three transformations- subtraction of the far-field expression for the interactions, phase correction and modified radial distance- applied successively to the pre-computed interactions. After obtaining the harmonic-polynomial expressions, the computation time for the reaction integral between two MBFs is independent from the complexity of the antenna array element.

Published
2011

33. Reduced-Size Double-Shell Lens Antenna With Flat-Top Radiation Pattern for Indoor Communications at Millimeter Waves

Author

Laurent Le Coq, Ronan Sauleau, Ngoc Tinh Nguyen, Institut d'Electronique et de Télécommunications de Rennes (IETR), Centre National de la Recherche Scientifique (CNRS)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Physics, Geometrical optics, business.industry, 020208 electrical & electronic engineering, Physics::Optics, 020206 networking & telecommunications, 02 engineering and technology, Physical optics, 7. Clean energy, law.invention, Radiation pattern, Lens (optics), Wavelength, Optics, law, Extremely high frequency, 0202 electrical engineering, electronic engineering, information engineering, Millimeter, Electrical and Electronic Engineering, Antenna (radio), business, ComputingMilieux_MISCELLANEOUS
Abstract

We investigate the capabilities of reduced-size integrated lens antennas to produce flat-top radiation patterns for broadband wireless communication systems at millimeter waves. The main challenge consists in controlling accurately the lens radiation performance over a broad frequency band while reducing its size; this constitutes a difficult task since producing highly shaped beams usually leads to oversized lens antennas. The design procedure is based on the geometrical optics/physical optics method (GO/PO), and the antenna characteristics are confirmed by full-wave simulations since the antenna size is only a few wavelengths. Our numerical results demonstrate that one anti-reflection coating is necessary even if the lens is made in a low-permittivity material (Rexolite). The resulting double-shell dielectric lens antenna has been fabricated and measured. The experimental results are in very good agreement with the simulations, and the radiation characteristics are stable over a 14% relative bandwidth, which is enough for broadband communications at millimeter waves.

Published
2011

34. Multi-Beam Multi-Layer Leaky-Wave SIW Pillbox Antenna for Millimeter-Wave Applications

Author

Ronan Sauleau, Laurent Le Coq, Mauro Ettorre, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Patch antenna, Physics, Coaxial antenna, business.industry, 020208 electrical & electronic engineering, Antenna measurement, 020206 networking & telecommunications, 02 engineering and technology, Antenna factor, Antenna rotator, 7. Clean energy, Antenna efficiency, law.invention, Microstrip antenna, Optics, law, 0202 electrical engineering, electronic engineering, information engineering, Dipole antenna, Electrical and Electronic Engineering, business, ComputingMilieux_MISCELLANEOUS
Abstract

This work proposes a novel multi-beam leaky-wave pillbox antenna. The antenna system is based on three main parts: feeding part (integrated horns), quasi-optical system and radiating part. The radiating and input parts are placed in two different stacked substrates connected by an optimized quasi-optical system. In contrast to conventional pillbox antennas, the quasi-optical system is made by a pin-made integrated parabola and several coupling slots whose sizes and positions are used to efficiently transfer the energy coming from the input part to the radiating part. The latter consists of a printed leaky-wave antenna, namely an array of slots etched on the uppermost metal layer. Seven pin-made integrated horns are placed in the focal plane of the integrated parabola to radiate seven beams in the far field. Each part of the antenna structure can be optimized independently, thus facilitating and speeding up the complete antenna design. The antenna concept has been validated by measurements (around 24 GHz) showing a scanning capability over ±30° in azimuth and more than 20° in elevation thanks to the frequency scanning behavior of the leaky-wave radiating part. The proposed antenna is well suited to low-cost printed circuit board fabrication process, and its low profile and compactness make it a very promising solution for applications in the millimeter-wave range.

Published
2011

35. A Fast Hybrid Method for Scattering From a Large Object With Dihedral Effects Above a Large Rough Surface

Author

Christophe Bourlier, Gildas Kubicke, DGA Maîtrise de l'information (DGA.MI), Direction générale de l'Armement (DGA), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Charlier, Sandrine, and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Radar cross-section, Scattering, Iterative method, Gaussian, Numerical analysis, Mathematical analysis, 0211 other engineering and technologies, 020206 networking & telecommunications, Geometry, 02 engineering and technology, Dihedral angle, Physical optics, symbols.namesake, 0202 electrical engineering, electronic engineering, information engineering, symbols, Electrical and Electronic Engineering, Gaussian process, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, Mathematics
Abstract

A new hybrid numerical method is described for scattering from an electrically large perfectly-conducting object with dihedral effects above a very long one-dimensional rough surface (two-dimensional problem). Such a problem involves a large number of unknowns and cannot be solved easily with a conventional method of moments by using a direct LU inversion. Thus, to solve this issue, the Extended-PILE method is combined with the forward-backward spectral acceleration (FBSA) for the local interactions on the rough surface and with the second-order physical optics (PO2) approximation for the local interactions on the object. Classically objects under test do not present dihedral effects and in the high frequency domain the first-order PO (PO1) provides the main contribution. In opposite, in this paper since a cross is considered, the second-order inner reflections contribute significantly and the PO2 must be included. By assuming a Gaussian process with a Gaussian height spectrum, this new hybrid method, E-PILE+FBSA+PO2, is tested against the rigorous E-PILE+ FBSA method (direct LU inversion on the object) as functions of the object inclination, the polarization and the incidence angle.

Published
2011

36. The Effect of Insulating Layers on the Performance of Implanted Antennas

Author

Juan R. Mosig, F. Merli, Benjamin Fuchs, Anja K. Skrivervik, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Power transmission, Medical Device Radiocommunications Service, Materials science, Electromagnetics, business.industry, Acoustics, Physics::Medical Physics, Electromagnetic radiation, Antenna efficiency, Dipole, Optics, Electrical and Electronic Engineering, Antenna (radio), business, Magnetic dipole, ComputingMilieux_MISCELLANEOUS
Abstract

This work presents the analysis of the influence of insulation on implanted antennas for biotelemetry applications in the Medical Device Radiocommunications Service band. Our goal is finding the insulation properties that facilitate power transmission, thus enhancing the communication between the implanted antenna and an external receiver. For this purpose, it has been found that a simplified model of human tissues based on spherical geometries excited by ideal sources (electric dipole, magnetic dipole and Huygens source) provides reasonable accuracy while remaining very tractable due to its analytical formulation. Our results show that a proper choice of the biocompatible internal insulation material can improve the radiation efficiency of the implanted antenna (up to six times for the investigated cases). External insulation facilitates the electromagnetic transition from the biological tissue to the outer free space, reducing the power absorbed by the human body. Summarizing, this work gives insights on the enhancement of power transmission, obtained with the use of both internal, biocompatible and external, flexible insulations. Therefore, it provides useful information for the design of implanted antennas.

Published
2011

37. Fast Solutions of the 2D Inverse Scattering Problem Based on a TSVD Approximation of the Internal Field for the Forward Model

Author

Jérôme Idier, Yves Goussard, Jean-Jacques Laurin, P.-A. Barriere, Institut de Recherche en Communications et en Cybernétique de Nantes (IRCCyN), Mines Nantes (Mines Nantes)-École Centrale de Nantes (ECN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-PRES Université Nantes Angers Le Mans (UNAM)-Centre National de la Recherche Scientifique (CNRS), and École Polytechnique de Montréal (EPM)

Subjects
Approximation theory, Computation, Mathematical analysis, 0211 other engineering and technologies, Approximation algorithm, 020206 networking & telecommunications, 02 engineering and technology, Inverse problem, Singular value, Microwave imaging, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, Singular value decomposition, Inverse scattering problem, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, Mathematics
Abstract

An alternative formulation of the microwave tomography problem is proposed, in order to reduce the computation time of the inversion procedure. The well-known multiplicative regularized contrast source inversion method is used as reference algorithm. Our formulation is based on a truncated singular value decomposition of the matrix involved in the most computationally intensive operations of the inversion algorithm. After theoretical and practical investigation of the behavior of the singular values, it is shown that the corresponding approximation does not yield any significant degradation of the quality of the solutions even for large complex permittivity contrasts, while the computation times are reduced by a factor ranging between 1.1 and 6 with respect to the original method.

Published
2010

38. Design and Characterization of 60-GHz Integrated Lens Antennas Fabricated Through Ceramic Stereolithography

Author

Dominique Baillargeat, Mauro Ettorre, Ngoc Tinh Nguyen, L. Le Coq, Ronan Sauleau, Nicolas Delhote, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), MINACOM, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, business.industry, 020208 electrical & electronic engineering, Impedance matching, 020206 networking & telecommunications, 02 engineering and technology, 7. Clean energy, Antenna efficiency, law.invention, Lens (optics), Optics, law, Side lobe, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Reflection coefficient, Center frequency, business, Waveguide, Stereolithography
Abstract

Three integrated lens antennas made in Alumina and built through ceramic stereolithography are designed, fabricated and characterized experimentally in the 60-GHz band. Linear corrugations are integrated on the lens surface to reduce the effects of multiple internal reflections and improve the antenna performance. The lenses are excited by Alumina-filled WR-15 waveguides with an optimized dielectric impedance matching taper in E-plane. The main characteristics of the first two prototypes with corrugations of variable size are compared to those of a smooth lens without corrugation (third prototype). Experimentally their reflection coefficient is smaller than -10 dB between 55 GHz and 65 GHz, and their radiation characteristics (main beam, side lobe level, cross-polarization level) are very stable versus frequency. In particular, at the center frequency (60 GHz), the total antenna loss (including feed loss) is smaller than 0.9 dB and the radiation efficiency exceeds 80%.

Published
2010

39. Minimization of MEMS Breakdowns Effects on the Radiation of a MEMS Based Reconfigurable Reflectarray

Author

Erwan Fourn, Hassan Salti, Herve Legay, Raphaël Gillard, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Alcatel Alenia Space (ALCATEL ALENIA SPACE), ALCATEL, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Microelectromechanical systems, Computer science, business.industry, Aperture, Phased array, 020208 electrical & electronic engineering, Electrical engineering, 020206 networking & telecommunications, 02 engineering and technology, Radiation, Network topology, Radiation pattern, Microstrip antenna, 0202 electrical engineering, electronic engineering, information engineering, Redundancy (engineering), Electronic engineering, Minification, Electrical and Electronic Engineering, business, Error detection and correction
Abstract

We present an investigation of MEMS breakdowns effects on the radiation pattern of a MEMS based reconfigurable reflectarray. In addition, a correction procedure is proposed to minimize phase errors due to breakdowns. It takes advantage of the numerous possibilities offered by the refectarray's cell to achieve a given phase shift. Furthermore, a systematic methodology is proposed to assess cell's robustness to breakdowns by defining a cumulative root mean square error accounting for any possible MEMS failure. It is shown to provide a convenient means of comparing different possible cell topologies. Finally, it is also used to minimize the number of MEMS in the cell while preserving the necessary redundancy to limit phase errors.

Published
2010

40. A Broadband Folded Printed Quadrifilar Helical Antenna Employing a Novel Compact Planar Feeding Circuit

Author

Yahia M. M. Antar, Ala Sharaiha, Mathieu Caillet, Michel Clenet, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Axial ratio, business.industry, 020208 electrical & electronic engineering, Bandwidth (signal processing), 020206 networking & telecommunications, 02 engineering and technology, 7. Clean energy, Beamwidth, Microstrip antenna, Optics, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, Broadband, 0202 electrical engineering, electronic engineering, information engineering, Helical antenna, Electrical and Electronic Engineering, Reflection coefficient, Wideband, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

A broadband printed quadrifilar helical antenna employing a novel compact feeding circuit is proposed in this paper. This antenna presents an excellent axial ratio over a wide beamwidth, with a 29% bandwidth. A specific feeding circuit based on an aperture-coupled transition and including two 90° surface mount hybrids has been designed to be integrated with the quadrifilar antenna. Over the bandwidth, the measured reflection coefficient of the antenna fed by the wideband compact circuit has been found to be equal to or lower than -12 dB and the maximum gain varies between 1.5 and 2.7 dBic from 1.18 to 1.58 GHz. The half-power beamwidth is 150°, with an axial ratio below 3 dB over this range. The compactness of the feeding circuit allows small element spacing in array arrangements.

Published
2010

41. Layered Circular-Cylindrical Dielectric Lens Antennas—Synthesis and Height Reduction Technique

Author

Tin Komljenovic, Ronan Sauleau, Zvonimir Sipus, Laurent Le Coq, Faculty of Electrical Engineering and Computing [Zagreb] (FER), University of Zagreb, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Institut d'Electronique et de Télécommunications de Rennes (IETR), Centre National de la Recherche Scientifique (CNRS)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Permittivity, Materials science, business.industry, Plane (geometry), Particle swarm optimization, 020206 networking & telecommunications, 02 engineering and technology, Dielectric, Horizontal plane, 01 natural sciences, law.invention, 010309 optics, Lens (optics), Optics, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Cylindrical lens, Electrical and Electronic Engineering, business, Global optimization
Abstract

An accurate computer-aided-design tool has been developed for the synthesis of broadband layered circular-cylindrical dielectric lens antennas. It is based on the combination of a fast method of analysis formulated in the spectral domain with a global optimization algorithm based on the particle swarm optimization technique. Using this tool, the influence of the number of layers is studied for lenses of moderate size. We show that single-layer lenses with an optimum permittivity value have nearly the same radiation characteristics as optimized multi-layer configurations. Finally we introduce a new height reduction technique that allows reducing the lens size by almost a factor of two while retaining the fan-beam pattern capabilities of cylindrical lenses in the elevation plane as well as their axial-symmetry needed for beam scanning in the horizontal plane. Numerical results have been compared successfully with experimental ones from 26 to 40 GHz, to validate the analysis.

Published
2010

42. Pattern Reconfigurable Cubic Antenna

Author

S. Toutain, Julien Sarrazin, Stéphane Avrillon, Yann Mahe, Institut de Recherche en Energie Electrique de Nantes Atlantique EA4642 (IREENA), Institut Universitaire de Technologie Saint-Nazaire (IUT Saint-Nazaire), Université de Nantes (UN)-Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Institut Universitaire de Technologie - La Roche-sur-Yon (IUT La Roche-sur-Yon), Université de Nantes (UN)-Université de Nantes (UN), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche en Electrotechnique et Electronique de Nantes Atlantique EA4642 (IREENA), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Reconfigurable antennas, slots and cavity, Hardware_PERFORMANCEANDRELIABILITY, 02 engineering and technology, envelope correlation coefficient, law.invention, Radiation pattern, Optics, 0203 mechanical engineering, law, 0202 electrical engineering, electronic engineering, information engineering, Hardware_ARITHMETICANDLOGICSTRUCTURES, Electrical and Electronic Engineering, Omnidirectional antenna, pattern diversity, Physics, Reconfigurable antenna, PIN diode switches, business.industry, Antenna measurement, 020302 automobile design & engineering, 020206 networking & telecommunications, Antenna efficiency, Periscope antenna, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Antenna blind cone, Antenna (radio), business
Abstract

International audience; A new single-feed reconfigurable antenna for pattern diversity is presented in this paper. The proposed structure is based on a metallic cubic cavity which radiates through rectangular slots. The pattern reconfiguration is achieved with PIN diode switches by short-circuiting slots in their center. The designed antenna can switch between three different radiation patterns which radiate in a 4π steradian range and can receive any incident field polarizations. A prototype of the antenna, including PIN diodes and operating in the 5 GHz band, has been built to demonstrate the feasibility of the concept. Measurements have been conducted and three-dimensional radiation patterns are provided. Diversity performances are evaluated by calculating the envelope correlation coefficient.

Published
2009

43. Design Optimization of Multishell Luneburg Lenses

Author

Olivier Lafond, Sebastien Rondineau, L. Le Coqis, Mohamed Himdi, Benjamin Fuchs, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Department of Electrical and Computer Engineering [Boulder], University of Colorado [Boulder], Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Permittivity, Optimization problem, Luneburg, Physics::Optics, Relative permittivity, 02 engineering and technology, Directivity, law.invention, Inhomogeneous lenses, Optics, law, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS, Mathematics, business.industry, 020208 electrical & electronic engineering, 020206 networking & telecommunications, Luneburg lens, Minimax, Lens (optics), shells, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Norm (mathematics), antennas, business
Abstract

Guidelines are provided for designing multishell Luneburg lenses (LL) whatever the primary source is. Three different optimization problems that minimize three different norms of the discrepancy between the ideal relative permittivity and the reconstructed one with respect to the thickness and permittivity of each shell are detailed. The performances of the three so-optimized LL are compared by simulations with those of previously proposed approaches. The highest directivity is obtained for the minmax norm. An investigation of the influence of the number of shells on the lens antenna performances, directivity, sidelobe levels and aperture efficiencies for various lens diameters, is also proposed in order to better know how to choose these parameters. Finally, measurements done with a multishell Luneburg lens fed by a waveguide are compared with simulations to show, through excellent agreements between theory and measurements, the validity of this study

Published
2007

44. Performance of reduced size substrate lens antennas for Millimeter-wave communications

Author

Ronan Sauleau, Daniel Thouroude, Gaël Godi, Institut d'Electronique et de Télécommunications de Rennes (IETR), Centre National de la Recherche Scientifique (CNRS)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Diffraction, Parabolic antenna, Materials science, business.industry, 020206 networking & telecommunications, Astrophysics::Cosmology and Extragalactic Astrophysics, 02 engineering and technology, Input impedance, 01 natural sciences, Directivity, Microstrip, law.invention, Radiation pattern, 010309 optics, Lens (optics), Microstrip antenna, Optics, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, business, ComputingMilieux_MISCELLANEOUS
Abstract

This paper presents the theoretical performance (input impedance, -10 dB return-loss bandwidth, radiation patterns and surface efficiencies) of reduced size substrate lenses fed by aperture-coupled microstrip patch antennas. The diameter of the extended hemispherical homogeneous dielectric (/spl epsiv//sub r,lens/) lenses varies between one and five wavelengths in free-space, in order to obtain radiating structures whose directivity is comprised between 10 and 25 dB. A lot of configurations of lenses are investigated using the finite-difference time-domain methods technique and compared in the 47-50 GHz band as a function of their diameter, extension length and dielectric constant. In particular, the analysis of internal reflections-in time and frequency domains-shows that the latter have potentially a strong influence on the input impedance of small lens antennas, even for low values of /spl epsiv//sub r,lens/(2.2), whereas the usual limit (beyond which anti-reflection coatings are required) is /spl epsiv//sub r,lens/=4. We also demonstrate that the diffraction limit of reduced size lenses is reached for extension lengths varying between 50% and 175% of the extension of synthesized ellipses, depending on the lens material and diameter. Finally, we show that superdirective structures with surface efficiencies reaching 250% can be obtained with small lens diameters, justifying the interest in reduced size lens antennas.

Published
2005

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